3D memory device

Abstract

A three-dimensional (3D) memory device includes a memory cell array, a first sense amplifier and a second sense amplifier. The memory cell array includes lower memory cells respectively arranged in regions where lower word lines intersect with bit lines and upper memory cells respectively arranged in regions where upper word lines intersect with the bit lines. The first sense amplifier is connected to a first lower word line and performs a data sensing operation on a first lower memory cell connected between a first bit line and the first lower word line. The second sense amplifier is connected to a first upper word line and performs a data sensing operation on a first upper memory cell connected between the first bit line and the first upper word line. The data sensing operations of the first and second sense amplifiers are performed in parallel.

What is claimed is: 
     
       1. A three-dimensional (3D) memory device comprising:
 a memory cell array including a plurality of lower memory cells respectively arranged in regions where a plurality of lower word lines intersect with a plurality of bit lines and a plurality of upper memory cells respectively arranged in regions where a plurality of upper word lines intersect with the plurality of bit lines; 
 a first sense amplifier connected to a first lower word line of the plurality of lower word lines, the first sense amplifier configured to perform a data sensing operation on a first lower memory cell connected between a first bit line of the plurality of bit lines and the first lower word line by comparing a voltage of the first lower word line with a first reference voltage; and 
 a second sense amplifier connected to a first upper word line of the plurality of upper word lines, the second sense amplifier configured to perform a data sensing operation on a first upper memory cell connected between the first bit line and the first upper word line by comparing a voltage of the first upper word line with a second reference voltage, 
 wherein the data sensing operation of the first sense amplifier and the data sensing operation of the second sense amplifier are performed in parallel. 
 
     
     
       2. The 3D memory device of  claim 1 , further comprising:
 a control logic configured to control the first and second sense amplifiers such that a read operation for the first lower memory cell and a read operation for the first upper memory cell are performed in parallel, 
 wherein the control logic is further configured to control a pre-charge operation to be performed on the first lower word line and the first upper word line in a word line pre-charge period of the 3D memory device and control a pre-charge operation for the first bit line in a bit line pre-charge period of the 3D memory device after the word line pre-charge period. 
 
     
     
       3. The 3D memory device of  claim 2 , further comprising:
 a first word line pre-charge circuit configured to apply a first word line pre-charge voltage to the first lower word line in the word line pre-charge period; and 
 a second word line pre-charge circuit configured to apply a second word line pre-charge voltage to the first upper word line in the word line pre-charge period. 
 
     
     
       4. The 3D memory device of  claim 3 , wherein a voltage level of each of the first and second word line pre-charge voltages is a negative voltage. 
     
     
       5. The 3D memory device of  claim 2 , further comprising:
 a first row decoder arranged between the plurality of lower word lines and the first sense amplifier, the first row decoder including a plurality of first row switches respectively connected to a corresponding one of the plurality of lower word lines and configured to perform a selection operation on the plurality of lower word lines; and 
 a second row decoder arranged between the plurality of upper word lines and the second sense amplifier, the second row decoder including a plurality of second row switches respectively connected to a corresponding one of the plurality of upper word lines and configured to perform a selection operation on the plurality of upper word lines. 
 
     
     
       6. The 3D memory device of  claim 5 , wherein, in the bit line pre-charge period, at least one of a first row switch connected to the first lower word line from among the plurality of first row switches and a second row switch connected to the first upper word line from among the plurality of second row switches is configured to slightly turn on. 
     
     
       7. The 3D memory device of  claim 6 , wherein, in the bit line pre-charge period, a control signal having a weak-on level is applied to at least one of the first row switch and the second row switch, and
 wherein the weak-on level is a voltage level between an on level that turns on each of the first and second row switches and an off level that turns off each of the first and second row switches. 
 
     
     
       8. The 3D memory device of  claim 2 , further comprising:
 a column decoder including a plurality of column switches respectively connected to a corresponding one of the plurality of bit lines and configured to perform a selection operation on the plurality of bit lines; and 
 a bit line pre-charge circuit configured to apply a bit line pre-charge voltage to the first bit line in the bit line pre-charge period. 
 
     
     
       9. The 3D memory device of  claim 1 , wherein each memory cell of the plurality of lower memory cells and the plurality of upper memory cells includes a selection element and a variable resistance element connected in series, and
 wherein the variable resistance element includes a phase change material. 
 
     
     
       10. The 3D memory device of  claim 1 , wherein the memory cell array is formed on a first semiconductor layer,
 wherein the first and second sense amplifiers are formed on a second semiconductor layer, and 
 wherein the first semiconductor layer and the second semiconductor layer are stacked in a vertical direction and thus the 3D memory device has a cell over peripheral (COP) structure. 
 
     
     
       11. A three-dimensional (3D) memory device comprising:
 a first semiconductor layer and a second semiconductor layer stacked in a vertical direction, 
 wherein the first semiconductor layer includes a memory cell array including a plurality of lower memory cells respectively arranged in regions where a plurality of lower word lines intersect with a plurality of bit lines and a plurality of upper memory cells respectively arranged in regions where a plurality of upper word lines intersect with the plurality of bit lines, and 
 wherein the second semiconductor layer includes: 
 a first sense amplifier connected to a first lower word line of the plurality of lower word lines, the first sense amplifier configured to perform a data sensing operation on a first lower memory cell connected between a first bit line of the plurality of bit lines and the first lower word line; and 
 a second sense amplifier connected to a first upper word line of the plurality of upper word lines, the second sense amplifier configured to perform a data sensing operation on a first upper memory cell connected between the first bit line and the first upper word line. 
 
     
     
       12. The 3D memory device of  claim 11 , wherein the second semiconductor layer further includes:
 a control logic configured to control the first and second sense amplifiers such that a read operation for the first lower memory cell and a read operation for the first upper memory cell are performed in parallel, and 
 wherein the control logic is further configured to control a pre-charge operation to be performed on the first lower word line and the first upper word line in a word line pre-charge period and control a pre-charge operation for the first bit line in a bit line pre-charge period after the word line pre-charge period. 
 
     
     
       13. The 3D memory device of  claim 12 , wherein the second semiconductor layer further includes:
 a first word line pre-charge circuit configured to apply a first word line pre-charge voltage to the first lower word line in the word line pre-charge period; and 
 a second word line pre-charge circuit configured to apply a second word line pre-charge voltage to the first upper word line in the word line pre-charge period. 
 
     
     
       14. The 3D memory device of  claim 13 , wherein a voltage level of each of the first and second word line pre-charge voltages is a negative voltage. 
     
     
       15. The 3D memory device of  claim 12 , wherein the second semiconductor layer further includes:
 a first row decoder arranged between the plurality of lower word lines and the first sense amplifier, the first row decoder including a plurality of first row switches respectively connected to a corresponding one of the plurality of lower word lines to perform a selection operation on the plurality of lower word lines; and 
 a second row decoder arranged between the plurality of upper word lines and the second sense amplifier, the second row decoder including a plurality of second row switches respectively connected to a corresponding one of the plurality of upper word lines to perform a selection operation on the plurality of upper word lines. 
 
     
     
       16. The 3D memory device of  claim 15 , wherein, in the bit line pre-charge period, at least one of a first row switch connected to the first lower word line from among the plurality of first row switches and a second row switch connected to the first upper word line from among the plurality of second row switches is configured to slightly turn on and. 
     
     
       17. The 3D memory device of  claim 12 , wherein the second semiconductor layer further includes:
 a column decoder including a plurality of column switches respectively connected to a corresponding one of the plurality of bit lines and configured to perform a selection operation on the plurality of bit lines; and 
 a bit line pre-charge circuit configured to apply a bit line pre-charge voltage to the first bit line in the bit line pre-charge period. 
 
     
     
       18. A three-dimensional (3D) memory device comprising:
 a memory cell array including a plurality of lower memory cells respectively arranged in regions where a plurality of lower word lines intersect with a plurality of bit lines and a plurality of upper memory cells respectively arranged in regions where a plurality of upper word lines intersect with the plurality of bit lines; 
 a first row decoder including a plurality of lower row switches respectively connected to a corresponding one of the plurality of lower word lines, the first row decoder performing a selection operation on the plurality of lower word lines; 
 a second row decoder including a plurality of upper row switches respectively connected to a corresponding one of the plurality of upper word lines, the second row decoder performing a selection operation on the plurality of upper word lines; 
 a first sense amplifier connected to a first lower word line of the plurality of lower word lines, the first sense amplifier configured to perform a data sensing operation on a first lower memory cell connected between a first bit line of the plurality of bit lines and the first lower word line; and 
 a second sense amplifier connected to a first upper word line of the plurality of upper word lines, the second sense amplifier configured to perform a data sensing operation on a first upper memory cell connected between the first bit line and the first upper word line. 
 
     
     
       19. The 3D memory device of  claim 18 , wherein a first lower row switch connected to the first lower word line from among the plurality of lower row switches and a first upper row switch connected to the first upper word line from among the plurality of upper row switches are driven by the same row address. 
     
     
       20. The 3D memory device of  claim 18 , wherein the plurality of lower word lines further includes a second lower word line,
 wherein the plurality of lower row switches include a first lower row switch connected to the first lower word line, and a second lower row switch connected to the second lower word line, and 
 wherein the 3D memory device further comprises: 
 a third sense amplifier connected to the second lower word line, the third sense amplifier configured to perform a data sensing operation on a second lower memory cell connected between the first bit line and the second lower word line.